Breast cancer is the most common malignancy among women, but also occurs in men (1). Risk factors include female gender, age, family history, smoking, metabolic syndrome and genetic predisposition, among others. There are various types of breast cancer, with ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) being the most common. Triple-negative breast cancer, with malignant cells having low or absent HER2, estrogen receptor, and progesterone receptor expression, accounts for 10-15% of cases and is particularly aggressive.

HER2, also known as proto-oncogene Neu or ERBB2, is a member of the human epidermal growth factor receptor family of tyrosine kinases. GeneTex’s HER2 / ERBB2 antibody (GTX100509) specifically detects HER2 protein by WB and generates the expected expression pattern in HER2-positive breast tumor sections by IHC-P (Figure 1).

Estrogen Receptor Alpha (ERα) and Beta (ERβ) have distinct cellular distributions, regulate separate sets of genes, and oppose each other in breast cancer (2). ERα and ERβ have been extensively studied and targeted for the development of therapeutics against hormone-positive breast cancer. GeneTex’s Estrogen Receptor Alpha antibody [1F3] (GTX70171) is a mouse monoclonal antibody whose sensitivity and specificity have been stringently validated by GeneTex and in multiple publications. The Estrogen Receptor Beta antibody [14C8] (GTX70174) is one of the most commonly used reagents to detect ERβ with more than one hundred citations (Figure 2).

The progesterone receptor (PR) is a well-known estrogen receptor (ER) target gene that is expressed in over two-thirds of ER-positive breast cancers (3). It acts as a transcriptional regulator and activator of signal transduction pathways (i.e., MAPK, PI3K/Akt, and c-Src) that can drive proliferative signaling in breast cancer cells (4). GeneTex’s Progesterone Receptor antibody [N1], N-term (GTX116051) was developed for IHC-P. It demonstrates distinct staining differences on PR-negative and PR-positive breast tumor tissue sections (Figure 3).

Some inherited mutations in BRCA1 are established drivers of breast cancer. GeneTex’s BRCA1 antibody [17F8] (GTX70111) is a highly cited monoclonal antibody validated for various applications including WB, ICC/IF, IHC-P, IP, ELISA, and ChIP (Figure 4).